Watertight joint compound/mud pan and method of manufacture

ABSTRACT

A drywall joint compound or mud pan is constructed as a folded type rectangular container from a single blank of metal. The pan has a flat bottom, and two sidewalls and two end walls that extend upwardly and laterally outward from the bottom. Triangular sections of metal are formed at each corner and folded over an adjacent end wall. Preferably, one sidewall makes a sharp angle with the bottom section and the opposing sidewall has a radius of sufficient size, which will permit the rapid removal of material from said pan.

RELATED APPLICATION

This application claims the benefit of provisional application Ser. No.60/687,423, filed Jun. 3, 2005.

FIELD OF THE INVENTION

This invention relates to containers or pans used to contain jointcompound or mud. A worker, more specifically, a drywall finisher orplasterer, while holding the pan in one hand containing joint compoundremoves a portion of joint compound and applies the joint compound to aspecific surface with a putty knife or taping knife.

BACKGROUND OF THE INVENTION

The use of drywall panels or sheet rock in the construction of interiorwall sections is widely known. Joint compound is applied to panel seamsto set drywall tape and thereafter so as to render the seam invisibleonce the sections are painted or prepared for further texturization.During this process a drywall finisher or worker uses a container ofsufficient size to hold an amount of joint compound using a putty knifeor taping knife to apply joint compound to said joint. The jointcompound employed in this process is usually a powder mixed with wateror aqueous material or ready-mix available in a variety of sizes.Powdered joint compound material is typically mixed in a largercontainer and transferred to a joint compound pan. In some cases thejoint compound pan is used as the mixing vessel thereby eliminating theneed to transfer the material. Ready-mix joint compound is oftentransferred from a master container, i.e. a five-gallon bucket, to thejoint compound pan for application. When setting joint tape, asubstantial amount of joint compound is applied to the seam. The tape isthen set into the wet joint compound and smoothed with a taping knife toremove excess joint compound and air pockets. This procedure allows forthe expanding and contraction of the wallboard panels without developingcracks between the wallboard panels. Drywall screws and nails are alsocovered with joint compound applied thereto by the knife. It istherefore advantageous to employ the use of a joint compound pan, whichallows the rapid removal of a large amount of joint compound. In bothcases, whether using a powdered joint compound or ready-mix, the jointcompound is often thinned in subsequent applications to seams to renderthe seams as smooth as possible. When using a thinned joint compound, itis often advantageous to have a sharp angular pan bottom to pinch-off orregulate the amount of compound on the taping knife for subsequentapplications.

A variety of joint compound pans have been developed. U.S. Pat. No.6,575,328 granted to Foraker discloses a joint compound container andinsulating pad similar to that show in FIGS. 1 and 2. Foraker does notdisclose the way the joint compound pan is constructed other than to sayit is a hollow metal pan. A commercially available version of this jointcompound pan is a three-piece design wherein the endcaps or end wallsare welded to the main body via spot welding or electrical resistancewelding. A pan of this design and construction will leak when filledwith an aqueous solution as is done to mix or thin joint compound.Second, this type of joint compound pan is more difficult to manufacturebecause of the three-piece design. Third, the end wall is constructedfrom a single material thickness usually of a thickness significantlyless than the body making the pan weak and flimsy.

U.S. Pat. No. 5,603,428 granted to Breckwoldt discloses to a jointcompound pan similar to that shown in FIG. 2. Breckwoldt writes, “Theend walls 29 are welded to the bottom wall 19 at opposite ends thereofin conventional fashion.” This can be accomplished one of two ways withrespect to welding. First, the endcap can be attached in a fashionsimilar to that used to make the Foraker pan shown in FIG. 1 of thispatent, via simple spotwelds. As previously noted there are leakageproblems with this construction. Alternatively, the endcap or end wallcan be attached with a continuous mig, tig, or heli-arc weld. FIG. 3shows a joint compound pan with the continuous weld. The pan shown inFIG. 3 is also available from companies such as Kraft, Stanley andMarshalltown. With this manufacturing technique, a continuous weld isachieved around the periphery of the endcap where it makes contact withthe bottom or main body. Although this technique usually achieves awatertight pan, other disadvantages exist. This manufacturing techniqueis costly. It is widely known in manufacturing circles that welding is arelatively expensive process compared to stamping, forming, and folding.

Another prior art joint compound pan shown in FIG. 4 is manufacturedfrom plastic. While remaining the most economical form of manufacturing,disadvantages exist. Plastic construction lacks the necessary strengthrequired for long-term use in a construction environment. It is easilycracked or chipped when dropped or handled roughly. Therefore, it israrely considered for the finishing professional. Furthermore, it has aremovable steel blade that when positioned into the plastic slot, actsas the straight-edge used to clean the taping knife. This preformed slotoften accumulates excess joint compound where it quickly dries. Thesesmall dried chunks of joint compound create major problems for thefinisher when they are dragged over the seam. Instead of leaving asmooth surface, the dried chunks leave grooves, which need continualsmoothing until such grooves disappear.

Edwards et al. in U.S. Pat. No. 6,454,124 disclose a four-piece jointcompound pan. Three of the four parts are made from plastic injectionmolding or similar while the center portion is typically constructed ofmetal. The endcaps are molded with foot members, which extend below thecenter portion. While this feature may be handy lifting the pan off of aflat table, it is difficult or nearly impossible to steady the pan ontop of a ladder or on a 5 gallon bucket of joint compound. If all fourfoot members do not contact a flat surface, the joint compound pan restson the rounded bottom easily tipping over. Furthermore, foot members areeasily broken if the pan is dropped thereby rendering the pan uselesswithout all four foot members. For these reasons this pan is both costlyand impractical.

It would be highly advantageous, therefore to remedy the foregoing andother deficiencies inherent in prior art. Accordingly, we provide ajoint compound pan having one bottom radius between the bottom and onesidewall with sufficient radius to allow the rapid removal of largequantities of joint compound. We further provide a joint compound panwith one sharp angular bottom radius between the bottom and one sidewallto allow the removal of a controlled amount of joint compound. Our panis watertight to contain a thinned mix of joint compound.

We construct our joint compound pan from a single blank or piece ofmaterial, usually metal, with folded corners defining the watertightproperties. The folded corner construction significantly increases thestrength of the joint compound pan, which is especially useful in ruggedconstruction environments.

Our pan has a triple end wall design which results in a stronger pan,the strength being achieved by folding the material on itself. Thepresent invention is highly impact resistant especially when dropped orresistant to twisting when full of joint compound.

Specific objects and advantages of the present invention will becomereadily apparent to those skilled in the art from the following detaileddescription of certain present preferred embodiments thereof shown thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of one type of prior art joint compoundpan having spot welded endcaps;

FIG. 2 is bottom perspective view of the prior art pan shown in FIG. 1;

FIG. 3 is a top perspective view of another type of prior art jointcompound pan with a continuously welded endcap;

FIG. 4 is a top perspective view of yet another type of prior art jointcompound pan constructed with plastic;

FIG. 5 is a top perspective view illustrating a present preferredembodiment of our joint compound pan;

FIG. 6 is a top view of a single blank or piece of material used in theconstruction of the joint compound pan shown in FIG. 5;

FIG. 7 is a perspective view of a partially formed pan of the type shownin FIG. 5; and

FIG. 8 is a perspective view of a second present preferred embodiment ofour joint compound pan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the drawings in which like reference characters indicatecorresponding elements throughout the several views, attention is firstdirected to FIGS. 5 through 8 which illustrate a joint compound pan ormud pan indicated at 10 and constructed in accordance with the teachingsof this present invention. Mud pan 10 comprises an open top 11, a bottom12, sidewalls 13, 15 end walls 17. Sidewall 13 and sidewall 15 generallyopposite and diverging upwardly and outwardly from bottom 12 and arejoined to end walls 17. As viewed from above, the open top 11 isrectangular in appearance. The bottom 12, end walls 17, and sidewalls 13and 15 define a volume for containing joint compound or other materialtherein. Upper edges 22, 14, and 16 define the periphery of opening 11while the mud pan 10 is accessible through the open top 11. The mud pan10 is of sufficient length to allow the entry of a drywall taping knife.Openings 11 may be 12″ to 14″ by 4″. The pan is constructed from asuitable material, preferably stainless steel, galvanized steel or othermetals and metal alloys which are corrosion resistant and have a minimumthickness 0.022 inches or 26 gauge. We prefer to use 22 gauge steelwhich has a thickness of from 0.028 inches to 0.030 inches.

Sidewall 13 meets bottom 12 along a corner radius 19 and has alongitudinal upper edge 14. The larger radius 19 is sufficiently largeor gradual to permit joint compound to be withdrawn from the mud pan 10by a natural scooping motion. This radius may vary from about one halfinch to one inch. This large radius is especially useful when firstapplying large amounts of joint compound and tape to seams. Sidewall 15is joined to bottom 12 with a smaller radius 21 and has a longitudinalupper edge 16. The smaller radius 21, typically one sixteenth inch orless, permits the drywall finisher to pinch-off smaller amounts of jointcompound when subsequently thinned layers of joint compound are appliedto seams. This is also useful when covering nails or screw holes. Whenexcess joint compound is removed from a seam or nail holes, the excessis scraped over upper edge 14 or 16 and is often reused.

Mud pan 10 is constructed from a single blank 1 or piece of material,preferably configured as shown in FIG. 6. The blank has two long edges 2and a smaller width. The corners are cut to have two edges 3, 4 thatmeet at an acute angle. This blank shape will produce a rectangularjoint compound pan as shown in FIGS. 5, 7, and 8. By varying the sizeand shape of the blank shown in FIG. 6, any square or rectangular jointcompound pan can be manufactured.

We prefer to place the blank 1 in a cold forming press or on a coldforming die and then bend the sides of the blank to the shape shown inFIG. 7. At this stage of the forming process generally triangular cornersections 18 having overlaying sections of the blank material will extendfrom each corner of the pan. Radius corners 19 and 21 will have beenfully formed. As can be seen in FIG. 7 corner sections 18 prior tofolding against end walls 17 are essentially parallel or co-planar withsidewalls 13 and 15. At this point hemmed edges 20 are essentiallyparallel with bottom 12. Next, the material defining the corner sections18 is folded over against the outside surface of each end wall 17.

Once corner sections 18 are folded against end walls 17, hemmed edges 20are folded over to cover the sharp upper edges of corner sections 18 anddefine the top edge of end walls 17. When corner sections 18 are foldedover end walls 17, the corners of the mud pan 10 are comprised of threematerial thicknesses. This manufacturing method creates an extremelyrigid mud pan 10, which is highly resistant to warping and highly impactresistant. Due to the rugged nature of construction environments, thispresents a tremendous advantage over all other prior art. Having cornersections 18 extending the full depth of the pan allows mud pan 10 todefine a watertight volume. This is especially useful when the mud pan10 contains liquids or thinned joint compound. Furthermore, themanufacturing method prescribed is more cost effective thereby creatinganother advantage over other prior art. The unique shape also permits aplurality of mud pans to be stacked or nested for storage, shipping,etc.

We prefer to provide a joint compound pan having a sharp radius 21 onone bottom edge and a gradual radius 19 along the opposite bottom edgeas shown in FIGS. 5 and 7. However, the process described with respectto forming the blank shown in FIG. 6 can be used to provide two sharpradii or two gradual radii along the bottom edge. A second presentpreferred embodiment shown in FIG. 8 has two sharp radii at 21 and 29.

Although we have shown and described certain present preferredembodiments of our joint compound pan and method of making same itshould be distinctly understood that our invention is not limitedthereto, but may be variously embodied within the scope of the followingclaims.

1. A joint compound formed from a blank of a selected materialcomprising: a bottom, a pair of spaced apart sidewalls attached to thebottom, and a pair of spaced apart end walls attached to the bottom andto the sidewalls, each end wall having an inside surface and an outsidesurface, a first pair of generally triangular end portions eachcomprised of two overlapping sections of the material and overlaying theoutside surface of one end wall, and a second pair of generallytriangular end portions each comprised of two other overlapping sectionsof the material and overlaying the outside surface of the other endwall.
 2. The joint compound pan of claim 1 also comprising a hemmed edgeextending from each end wall and folded over the triangular end portionsoverlaying that end wall.
 3. The joint compound pan of claim 1 wherein:a first radius is formed between the bottom and one of the pair ofsidewalls, a second radius is formed between the bottom and the otherone of the pair of sidewalls, and the first radius is greater than thesecond radius.
 4. The joint compound pan of claim 3 wherein the firstradius is between one sixteenth inch and one inch.
 5. The joint compoundpan of claim 3 wherein the second radius is not greater than onesixteenth inch.
 6. The joint compound pan of claim 1 wherein thematerial is metal.
 7. The joint compound pan of claim 6 wherein thematerial is selected from the group of metals consisting of stainlesssteel, galvanized steel and corrosion resistant metal alloys.
 8. Thejoint compound pan of claim 1 wherein: a first radius is formed betweenthe bottom and one of the pair of sidewalls, a second radius is formedbetween the bottom and the other one of the pair of sidewalls, and thefirst radius and second radius are equal.
 9. The joint compound of claim8 wherein the first radius and the second radius are not greater thanone-sixteenth inch.
 10. A method of forming a joint compound pancomprising; selecting a generally rectangular blank having a pair oflong edges and a pair of short edges, the blank comprised of a selectedmaterial, folding portions of the blank adjacent each long edge tocreate a pair of spaced apart sidewalls extending from a bottom andhaving first radius formed between the bottom and one of the pair ofsidewalls and a second radius formed between the bottom and the otherone of the pair of sidewalls, folding portions of the blank adjacenteach short edge to create a pair of spaced-apart end walls each end wallhaving an outside surface, such that after the sidewalls and the endwalls are formed there will be four corners where an end wall meets aside wall, each corner having a generally triangular end portionextending from the corner, each generally triangular end portioncomprised of two overlapping sections of the material, and folding eachgenerally triangular end portion over the outside surface of one of theend walls.
 11. The method of claim 10 also comprising folding an edge ofeach end wall over the generally triangular end portions overlaying thatend wall.
 12. The method of claim 10 wherein the selected material isselected from stainless steel, galvanized steel and corrosion resistantmetal alloys.
 13. The method of claim 10 wherein: a first radius isformed between the bottom and one of the pair of sidewalls, a secondradius is formed between the bottom and the other one of the pair ofsidewalls, and the first radius is greater than the second radius. 14.The method of claim 13 wherein the first radius is between one sixteenthinch and one inch.
 15. The method of claim 13 wherein the second radiusis not greater than one sixteenth inch.